rina I was answering the ? on a ficus. it is my opinion a thin layer of sand ON TOP about a 1/2in you still get airation you just do not have to water as often. You will have to experiment with how much water you give it cause it will be less and sand still compacts enough to kill the eggs (has to be coarse sand) .does not effect drainage if using right medium with good pots with alot of drainage holes it take alil longer to go threw the sand if you pouring water on top and get a more even watering to go threw the sand. But when i use organics and also making compost tea with the heat from the lights i got this problem.But I am activating the micro organisms with air pump to maximize the organics that im buying and using in media and teas so i go threw alot less fertilizers when i feed and when I water the roots are getting air h20 from the water.But this is how i got fungus gnats with the organics and the heat from my lights and how i cured my problem was with sand. I dont water every day or every other day cause in my soil i use coconut fiber,sand, and other media which retains some moisture and it gives it more time before I water again. I only feed once or twice a month and water in between depending on my plants When i have grown lilac trees using organics i had a good pearl white root zone.It also depends on what you are growing succulents most of them only get watered twice a month . Also some succlulents do prefer a sandy soil cactus is part of the succulent family what do they grow in?Also there are other succulents that prefer sandy soil too or peat or rock. Check further down in container gardening there is a thread called water release curve for growing media ingredent. But in the end it is what works best for you and what results you want to achieve and how much you want to experiment,research and read . This is what works good for me.

Rodney, thank you. The soil is almost certainly the problem...I bought it during a pandemic moment of panic when I needed something and local nurseries were closed or had extremely long lines. It’s organic, but from Home Depot. I swore once I’d never buy it there again (last time I did, I also got fungus gnats bad). My mom swears by heating the soil in the oven. I’ve never tried it. I’ll try mosquito dunks. About the peas...I’m in Bay Area, California, so I suppose it’s too hot, though evenings are still cool. I just don’t understand why the lower parts are dying first. They get less sun/heat because of the shade of the balcony wall. I guess we’ll replant in the fall, now that I know they’ll grow in this pot.

Fungus gnats thrive in an warm, wet, environment where there is a reliable supply of rotting organic matter. If you are using a bagged potting medium comprised of fine materials like peat, coir, compost, composted forest products, sand, etc,. and follow the advice to water when the top inch or two of soil becomes dry to the touch, the primary cause of the gnat problem would go under the heading of grower error. Unless your pot is very shallow, 5" deep or less, the advice to water when the top inch or two of soil is dry is a recipe for over-watering. If you are using an 8" deep pot and water when the top 2 inches of soil feels dry, you could easily be watering when the lower 5-6" of the medium is still 100% saturated with water. Using a wooden dowel as a "tell" to "tell" you when it's time to water is a good way to keep plants much healthier and avoid fungus gnat infestations. Here is something about using a "tell", and there ARE alternatives to changing your soil. Before I get into that, how large are the plants we're talking about - something easily handled over the sink or something it takes significantly greater effort to move around? Using a 'tell' Over-watering saps vitality and is one of the most common plant assassins, so learning to avoid it is worth the small effort. Plants make and store their own energy source – photosynthate - (sugar/glucose). Functioning roots need energy to drive their metabolic processes, and in order to get it, they use oxygen to burn (oxidize) their food. From this, we can see that terrestrial plants need plenty of air (oxygen) in the soil to drive root function. Many off-the-shelf soils hold too much water and not enough air to support the kind of root health most growers would like to see; and, a healthy root system is a prerequisite to a healthy plant. Watering in small sips leads to avoid over-watering leads to a residual build-up of dissolved solids (salts) in the soil from tapwater and fertilizer solutions, which limits a plant's ability to absorb water – so watering in sips simply moves us to the other horn of a dilemma. It creates another problem that requires resolution. Better, would be to simply adopt a soil that drains well enough to allow watering to beyond the saturation point, so we're flushing the soil of accumulating dissolved solids whenever we water; this, w/o the plant being forced to pay a tax in the form of reduced vitality, due to prolong periods of soil saturation. Sometimes, though, that's not a course we can immediately steer, which makes controlling how often we water a very important factor. In many cases, we can judge whether or not a planting needs watering by hefting the pot. This is especially true if the pot is made from light material, like plastic, but doesn't work (as) well when the pot is made from heavier material, like clay, or when the size/weight of the pot precludes grabbing it with one hand to judge its weight and gauge the need for water. Fingers stuck an inch or two into the soil work ok for shallow pots, but not for deep pots. Deep pots might have 3 or more inches of soil that feels totally dry, while the lower several inches of the soil is 100% saturated. Obviously, the lack of oxygen in the root zone situation can wreak havoc with root health and cause the loss of a very notable measure of your plant's potential. Inexpensive watering meters don't even measure moisture levels, they measure electrical conductivity. Clean the tip and insert it into a cup of distilled water and witness the fact it reads 'DRY'. One of the most reliable methods of checking a planting's need for water is using a 'tell'. You can use a bamboo skewer in a pinch, but a wooden dowel rod of about 5/16” (75-85mm) would work better. They usually come 48” (120cm) long and can usually be cut in half and serve as a pair. Sharpen all 4 ends in a pencil sharpener and slightly blunt the tip so it's about the diameter of the head on a straight pin. Push the wooden tell deep into the soil. Don't worry, it won't harm the root system. If the plant is quite root-bound, you might need to try several places until you find one where you can push it all the way to the pot's bottom. Leave it a few seconds, then withdraw it and inspect the tip for moisture. For most plantings, withhold water until the tell comes out dry or nearly so. If you see signs of wilting, adjust the interval between waterings so drought stress isn't a recurring issue. Al

Sorry, roseseek. What a dunderhead I am! I guess I was confusing this with the label directions and hadn't even read the above link! Wow! Thank you again. I applied it as directed and it has definitely helped. I still may spray some neem, but so far the drench seems to have eliminated everything. I just hope they didn't kill one of my cuttings. : (( Summers, just a warning not to use too much soap. I killed a couple of sensitive houseplants last year doing that. I guess the ratio was off.